Tree line in the context of Hoary marmot

In physical geography, a tundra (/ˈtʌndrə, ˈtʊn-/) is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: Arctic, Alpine, and Antarctic.

Tundra vegetation is composed of dwarf shrubs, sedges, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink. As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-contained greenhouse gases into the atmosphere, creating a feedback cycle that contributes to climate change.

Alpine climate is the typical climate for elevations above the tree line, where trees fail to grow due to cold. This climate is also referred to as a mountain climate or highland climate.

An alpine lake is a high-altitude lake in a mountainous area, usually near or above the tree line, with extended periods of ice cover. These lakes are commonly glacial lakes formed from glacial activity (either current or in the past) but can also be formed from geological processes such as volcanic activity (volcanogenic lakes) or landslides (barrier lakes). Many alpine lakes that are fed from glacial meltwater have the characteristic bright turquoise green color as a result of glacial flour, suspended minerals derived from a glacier scouring the bedrock. When active glaciers are not supplying water to the lake, such as a majority of Rocky Mountains alpine lakes in the United States, the lakes may still be bright blue due to the lack of algal growth resulting from cold temperatures, lack of nutrient run-off from surrounding land, and lack of sediment input. The coloration and mountain locations of alpine lakes attract lots of recreational activity.

Alpine lakes are some of the most abundant types of lakes on Earth. In the Swiss Alps alone, there are nearly 1,000 alpine lakes, most of which formed after the Little Ice Age. As global temperatures continue to rise, more alpine lakes will be formed as glaciers recede and provide more run-off to surrounding areas, and existing lakes will see more biogeochemical changes and ecosystem shifts. An alpine lake's trophic state (i.e., level of biological productivity) progresses with age (e.g., low productivity after formation and increased productivity with vegetation and soil maturity in the surrounding watershed), but anthropogenic effects such as agriculture and climate change are rapidly affecting productivity levels in some lakes. These lakes are sensitive ecosystems and are particularly vulnerable to climate change due to the highly pronounced changes to ice and snow cover. Due to the importance of alpine lakes as sources of freshwater for agricultural and human use, the physical, chemical, and biological responses to climate change are being extensively studied.

Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation, with an associated harsh climate. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level and merges with polar tundra.

The high elevation causes an adverse climate, which is too cold and windy to support tree growth. Alpine tundra transitions to sub-alpine forests below the tree line; stunted forests occurring at the forest-tundra ecotone are known as krummholz. With increasing elevation it ends at the snow line where snow and ice persist through summer.

The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. The line separates the clockwise Antarctic circumpolar current from other oceans. Antarctic waters predominantly sink beneath the warmer subantarctic waters, while associated zones of mixing and upwelling create a zone very high in marine productivity, especially for Antarctic krill.

This line, like the Arctic tree line, is a natural boundary rather than an artificial one, such as the borders of nations and time zones. It not only separates two hydrological regions, but also separates areas of distinctive marine life and climates.

Intermontane is a physiographic adjective formed from the prefix "inter-" (signifying among, between, amid, during, within, mutual, reciprocal) and the adjective "montane" (inhabiting, or growing in mountainous regions, especially cool, moist upland slopes below the timberline).

The corresponding physiographic noun is intermountain, while the noun intermontane is an ecologic noun meaning among, between, amid, or within "flora and fauna of a montane habitat." As an example, an alpine region would be an intermontane for a species that migrates between a glacial region and a subalpine region.

Fell (from Old Norse: fell, "mountain → landscape over the tree line"; cf. Icelandic: fell, Norwegian: fjell, Swedish: fjäll) is a high and barren landscape feature, such as a mountain or moor-covered hill, often mountain landscape over the tree line, etc. The term is most often employed in Fennoscandia, Iceland, the Isle of Man, parts of northern England, and Scotland.

Pinus peuce (Macedonian pine or Balkan pine) (Serbo-Croatian and Macedonian: молика, molika; Bulgarian: бяла мура, byala mura) is a species of pine native to the mountains of North Macedonia, Bulgaria, Albania, Montenegro, Kosovo, the extreme southwest of Serbia, and the extreme northwest of Greece, growing typically at (600-) 1,000-2,200 (-2,300) m altitude. It often reaches the alpine tree line in this area. The mature size is up to 35–40 m height, and 1.5 m trunk diameter. However, the height of the tree diminishes strongly near the upper tree line and may even obtain shrub sizes.

It is a member of the white pine group, Pinus subgenus Strobus, and like all members of that group, the leaves ('needles') are in fascicles (bundles) of five, with a deciduous sheath. They are 6–11 cm long. Its pine cones are mostly 8–16 cm long, occasionally up to 20 cm long, green at first, becoming yellow-brown when mature, with broad, flat to downcurved scales. The 6–7 mm long seeds have a 2 cm wing and can be wind-dispersed, but are also very often dispersed by spotted nutcrackers.

Junipers are coniferous trees and shrubs in the genus Juniperus (/dʒuːˈnɪpərəs/ joo-NIP-ər-əs) of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere as far south as tropical Africa, as far north as the Arctic, and parts of Asia and Central America. The highest-known juniper forest occurs at an altitude of 4,900 metres (16,100 ft) in southeastern Tibet and the northern Himalayas, creating one of the highest tree lines on earth.

Wakhan National Park is a national park in northeastern Afghanistan. Established in 2014, the park encompasses the entire Wakhan District of Badakhshan Province, extending along the Wakhan Corridor between the Pamir Mountains and the Hindu Kush, bordering the Gorno-Badakhshan autonomous region of Tajikistan to the north, Khyber Pakhtunkhwa and Gilgit-Baltistan in Pakistan to the south, and the Xinjiang autonomous region of China to the east.

Flora and fauna in the Wakhan National Park include some 600 plant species, the snow leopard, lynx, wolf, brown bear, stone marten, red fox, Pallas's cat, ibex, Marco Polo sheep, and urial. Remote and largely above the tree line, poaching and overgrazing, rather than mining and logging, currently pose the main threats. Around 15,000 Afghans of ethnic Wakhi and Kyrgyz background reside in the area. Foreigners must have an Afghan visa to tour the area.

The White Goat Wilderness Area is a provincially designated wilderness area in the Canadian Rockies of Alberta. It was established in 1961 and it, as one of the three wilderness areas of Alberta, has the strictest form of government protection available in Canada. All development is forbidden and only travel by foot is permitted. Hunting and fishing are not allowed. The other two wilderness areas are Ghost River Wilderness Area and Siffleur Wilderness Area and together the three areas total 249,548.80 acres (100,988.82 ha).

White Goat is located near the west end and north side of Canadian Highway 11 and slightly north of the Siffleur Wilderness area. It is near the north end of Banff National Park, the south end of Jasper National Park, and east of the Columbia Icefield. Mountains rise to over 3,300 metres (10,800 ft). The area has rugged mountains, glacier-carved valleys, mountain lakes, waterfalls, and alpine meadows. There are two distinct vegetation zones. Above 2,100 metres (6,900 ft), the tree line, are grasses, sedges and wildflowers. Below that are spruce, fir, and lodgepole pine. Animals in the lower regions include woodland caribou, moose, elk, white-tailed deer, mule deer, grizzly bear, black bear, cougar, coyote, timber wolf, and wolverine. Animals in the upper regions include golden-mantled ground squirrels, bighorn sheep, mountain goat, hoary marmot, pika, white-tailed ptarmigan, grey-crowned rosy finch, water pipit and horned lark. Eagles are seen in both the lower and upper regions.

First Nations (French: Premières Nations) is a term used to identify Indigenous peoples in Canada who are neither Inuit nor Métis. Traditionally, First Nations in Canada were peoples who lived south of the tree line, and mainly south of the Arctic Circle. There are 634 recognized First Nations governments or bands across Canada. Roughly half are located in the provinces of Ontario and British Columbia.

Under federal employment equity law, First Nations are a "designated group", along with women, visible minorities, and people with physical or mental disabilities. First Nations are not included in the Statistics Canada visible minority category, as there is a separate category for First Nations, Metis and Inuit.

Inuktitut (/ɪˈnʊktətʊt/ ih-NUUK-tə-tuut; Inuktitut: [inuktiˈtut], syllabics ᐃᓄᒃᑎᑐᑦ), also known as Eastern Canadian Inuktitut, is one of the principal Inuit languages of Canada. It is spoken in all areas north of the North American tree line, including parts of the provinces of Newfoundland and Labrador, Quebec, to some extent in northeastern Manitoba as well as the Northwest Territories and Nunavut. It is one of the aboriginal languages written with Canadian Aboriginal syllabics.

It is recognized as an official language in Nunavut alongside Inuinnaqtun and both languages are known collectively as Inuktut. Further, it is recognized as one of eight official native tongues in the Northwest Territories. It also has legal recognition in Nunavik—a part of Quebec—thanks in part to the James Bay and Northern Quebec Agreement, and is recognized in the Charter of the French Language as the official language of instruction for Inuit school districts there. It also has some recognition in Nunatsiavut—the Inuit area in Labrador—following the ratification of its agreement with the government of Canada and the province of Newfoundland and Labrador. The 2016 Canadian census reports that 70,540 individuals identify themselves as Inuit, of whom 37,570 self-reported Inuktitut as their mother tongue.

Krummholz /ˈkrʊmˌhoʊlts/ (German: krumm, "crooked, bent, twisted" and Holz, "wood") — also called knieholz ("knee timber") — is a type of stunted, deformed vegetation encountered in the subarctic and subalpine tree line landscapes, shaped by continual exposure to fierce, freezing winds. Under these conditions, trees can survive only where they are sheltered by rock formations or snow cover. As the lower portion of these trees continues to grow, the coverage becomes extremely dense near the ground. In Newfoundland and Labrador, the formation is known as tuckamore. Krummholz trees are also found on beaches, such as the Oregon coast, where trees can become much taller than their subalpine cousins.

The labeling of diverse sets of tree species in different ecological contexts may be problematic. The ecological requirements of krummholz trees in the Alps, for example, are different from those in the Rockies. The terms scrub or shrubland may be more appropriate for some communities with krummholz trees.

The Inuvialuit Settlement Region (ISR; Inuinnaqtun: Inuvialuit Nunangit Sannaiqtuaq – INS; French: Région désignée des Inuvialuit – RDI), located in Canada's western Arctic, was designated in 1984 in the Inuvialuit Final Agreement by the Government of Canada for the Inuvialuit. It spans 435,000 km (270,000 mi), including 90,650 km (35,000 sq mi) of land and 12,980 km (5,010 sq mi) of subsurface mineral rights. The ISR is mainly above the tree line, and includes several sub-regions: the Beaufort Sea, the Mackenzie River delta, the northern portion of Yukon ("Yukon North Slope", Herschel Island), and the northwest portion of the Northwest Territories. The ISR includes both Crown Lands and Inuvialuit Private Lands. Most of the ISR is represented by Nunakput, the territorial electoral district, meaning "our land" in Inuvialuktun.

The ISR is one of the four Inuit regions of Canada, collectively known as Inuit Nunangat, represented by the Inuit Tapiriit Kanatami (ITK). The other regions include Nunatsiavut in Labrador, Nunavik in northern Quebec, and the territory of Nunavut. The ISR is the homeland of the Inuvialuit. The Inuvialuit Regional Corporation, established in 1986 as the receiver of the lands and financial compensation of the Inuvialuit Final Agreement, is controlled by the Inuvialuit population and is responsible for ISR operations. From 1996 until 2016, Nellie Cournoyea, former Premier of the Northwest Territories, was the Chair and CEO of the Board. She had been elected nine times before declining to run again. In 2016, Duane Ningaqsiq Smith, was elected to replace her, was re-elected in 2019, and acclaimed in 2022.

The North American Arctic is composed of the northern polar regions of Alaska (USA), Northern Canada and Greenland. Major bodies of water include the Arctic Ocean, Hudson Bay, the Gulf of Alaska and North Atlantic Ocean. The North American Arctic lies above the Arctic Circle. It is part of the Arctic, which is the northernmost region on Earth. The western limit is the Seward Peninsula and the Bering Strait. The southern limit is the Arctic Circle latitude of 66° 33’N, which is the approximate limit of the midnight sun and the polar night.

The Arctic region is defined by environmental limits where the average temperature for the warmest month (July) is below 10 °C (50 °F). The northernmost tree line roughly follows the isotherm at the boundary of this region. The climate of the region is known to be intensely cold during the year due to its extreme polar location. The area has tundra, Arctic vegetation, glaciers, and, for most of the year, is covered in thick blankets of snow and ice.